Tobacco smoke filter and method of production

ABSTRACT

A product rod comprising a plurality of individual tobacco smoke filters or filter elements abutted end to end; and a wrapper engaged around the plurality of filters or filter elements, the wrapper including perforations.

The present invention relates to tobacco smoke filters or filter elements and methods of their production.

Non-Wrapped Acetate (NWA) filters are well-known in the art. Typically, NWA filters comprise a self-sustaining body of continuous crimped cellulose acetate filaments bonded at their points of contact. NWA filters are characterized from conventional cigarette filters because the former do not require a separate plugwrap to wrap the filter and hold the fibrous bundle in place with a controlled circumference. NWA filters may be manufactured by a process similar to that described in UK Patent No. 1169932 (U33,455,766).

NWA filters may be sold as Pop-a-Tip™ filters for Roll-Your-Own (RYO) Smokers; they are well known and available from Filtrona Filters. Pop-a-Tip filters comprise a series of NWA filters (filter tips) wrapped in a transparent film e.g. made of BOPP or cellophane—e.g. six 14 mm filters contained in a Pop-a-Tip rod of 84 mm length. The NWA filters are individually pushed (or ‘popped’) out of the transparent wrap by smokers of RYO products, who then use the filter when rolling their cigarette. NWA filters are preferred over more conventional wrapped acetate (WA) filters, because it is much more difficult to ‘pop’ a WA filter from the transparent film due to increased frictional forces. However, the product can be tricky to use as a certain amount of dexterity is required to push the filter tips out from the surrounding film (e.g. some bending and flexing of the Pop-a-Tip may be necessary). In addition, the empty film-wrap needs to be separately discarded, creating a potential additional littering problem.

It is, of course, possible, for RYO smokers to buy loose individual tips and these are typically supplied in plastic bags. Such bags of tips are inconvenient for smokers to carry around; a further advantage of Pop-a-Tips is that they are of similar dimensions to a cigarette and can be packaged and sold in a packs that are much easier for the consumer to carry (e.g. similar to a cigarette pack).

Accordingly, it would be desirable to have a product that resembles a ‘Pop-a-Tip’ and can be packaged in a similar way; from which individual filters are more readily and easily extractable by the consumer; and which does not have the attendant expense and littering associated with the transparent overwrap. The present invention achieves these objectives.

According to the present invention in a first aspect there is provided a product rod comprising a plurality (e.g. two or more, e.g. 4-6) of individual tobacco smoke filters or filter elements abutted end to end; and a (common) wrapper engaged around the plurality of filters or filter elements, the wrapper including perforations. The individual tobacco smoke filters (or individual tobacco smoke filter elements) are preferably (substantially) identical (with each other). In other words, the product rod preferably comprises a plurality (e.g. two or more, e.g. 4-6) of individual identical tobacco smoke filters or individual identical filter elements abutted end to end; and a (common) wrapper engaged around the plurality of filters or filter elements, the wrapper including perforations.

According to the invention in a further aspect there is provided a product rod comprising a plurality (e.g. two or more, e.g. 4-6) of individual tobacco smoke filters or filter elements abutted end to end; and a (common) wrapper engaged around the plurality of filters or filter elements, the wrapper including a line of perforations (holes) in register with the or each junction between abutted filters or filter elements (that is, in register with each region where adjacent filters or filter elements abut each other). The individual tobacco smoke filters (or individual tobacco smoke filter elements) are preferably (substantially) identical (with each other). In other words, the product rod preferably comprises a plurality (e.g. two or more, e.g. 4-6) of individual identical tobacco smoke filters or individual identical filter elements abutted end to end; and a (common) wrapper engaged around the plurality of filters or filter elements, the wrapper including a line of perforations (holes) in register with the or each junction between abutted filters or filter elements.

Herein, the term identical means the same (equal, alike); in other words each individual filter has such a close similarity or resemblance to the others as to be essentially equal or interchangeable.

It will be appreciated that each (individual) filter may include more than one filter element. Thus, each (individual) filter may be a dual or triple filter, as is well known in the art.

The wrapper may be a paper (e.g. a plugwrap) or other sheet material. The paper is preferably a paper having basis weight of 15-50 gsm, more preferably 17-35 gsm. The paper may be air permeable, or impermeable (i.e. air impermeable except where the holes have been generated). The wrapper may be a cellulosic film or a cellulosic based film. The wrapper may be biodegradable. Preferably the wrapper has the ‘Ready Biodegradability’ level of biodegradability as measured according to OECD 301B ‘Ready Biodegradability’ method (modified Sturm test), which is well known in the art.

The product rod of the invention allows the smoker to easily pull or bend the product rod at each join (junction between abutted filters) to snap off individual filters/elements. The perforations (holes) at each junction between abutted filters/elements allow a clean break between abutting filters/elements to be achieved; a jagged break would be unsightly and unacceptable to the consumer. The (outer) wrapper of the snapped-off filter forms part of the filter tip to be used, rather than becoming redundant (as in the case of conventional Pop-a-Tips). Both WA (wrapped acetate) and NWA filters can be used in this product, increasing flexibility for the filter manufacturer.

Preferably the wrapper includes a line of 16 to 40, e.g. 16 to 39, e.g. 20 to 35, e.g. 30 to 35 perforations (holes) in register with the or each junction between abutted filters or filter elements. Preferably the wrapper includes a line of 20 to 35 perforations (holes) in register with the or each junction between abutted filters or filter elements, for a product rod of approximate circumference 17.5 mm. The wrapper may include a line of 20 to 40 perforations (holes) in register with the or each junction between abutted filters or filter elements, for a product rod of approximate circumference 17.5 mm. The perforations (holes) may be any shape, e.g. oval or rectangular. Preferably the perforations (holes) are symmetrical. Oval shaped perforations (holes) are more preferred because they provide a cleaner break in the paper. Rectangular or similar perforations (holes) may be aligned so that their longer side is orientated either across the width or along the length of the wrapper.

The perforations (holes) may be made by any means known in the art, e.g. laser, mechanical means or electrostatic means. Preferably, the perforations (holes) are visible to the naked eye (e.g sufficiently large that the consumer can see them on the outside of the product rod, enabling him to clearly identify the point at which the rod should be snapped). The (e.g. laser perforated) perforations (hole) dimensions may be 0.1 mm to 0.7 mm along one or both edges. The (e.g. laser perforated) perforations (holes) are preferably spaced at 10 to 25 holes per cm (along the line of perforations), more preferably 11 to 23 holes per cm (along the line of perforations). Preferably the perforations (holes) are of nominal dimensions 0.6 mm×0.3 mm, e.g. 0.4×0.2 mm. The applicants have found that perforations (holes) of this size give a good visual cue.

Research (see Example) has shown that 30 to 35 rectangular or oval shaped holes of nominal dimensions 0.4×0.2 mm around the circumference of a 17.9 mm circumference product rod provide optimum ‘snap’ characteristics. Less than around 15 holes of such size give an uneven ‘snap’ (e.g. with unacceptable tearing), whilst more than 40 holes can result in the paper wrapper being too weak to be processed on conventional filter making and/or packaging machinery. It will be appreciated that a proportionately greater or lesser number of holes would be required for filter products of higher or lower circumference.

According to the present invention in a still further aspect there is provided a product rod comprising a plurality of (e.g. two or more, e.g. 4 to 6) individual tobacco smoke filters or filter elements abutted end to end; and a (common) wrapper engaged around the plurality of filters or filter elements, the wrapper including a line of perforations extending from one end of the product rod to the other end and defining a helix about the periphery (outer surface) of the product rod. In this aspect the consumer peels back a strip along the helical line of perforations to allow filters/filter elements to be sequentially released for use, the remaining wrapper holding the remaining filters in place. The individual tobacco smoke filters (or individual tobacco smoke filter elements) are preferably (substantially) identical (with each other). In other words, the product rod preferably comprises a plurality (e.g. two or more, e.g. 4-6) of individual identical tobacco smoke filters or individual identical filter elements abutted end to end; and a (common) wrapper engaged around the plurality of filters or filter elements, the wrapper including a line of perforations extending from one end of the product rod to the other end and defining a helix about the periphery (outer surface) of the product rod.

In a preferred example, the pitch of the helix defined by the line of the perforations (that is the distance along the helical axis that results in one full turn of the helix) is the length of a single individual filter or filter element. In this example, peeling back the strip along the line of perforations for a single turn of the helix releases a single filter/filter element.

The perforations (holes) may be any shape, e.g. oval or rectangular. Preferably the perforations (holes) are symmetrical. Oval shaped perforations (holes) are more preferred because they provide a cleaner tear in the paper. The perforations (holes) may be made by any means known in the art, e.g. laser, mechanical means or electrostatic means. The (e.g. laser perforated) perforations (hole) dimensions may be 0.1 mm to 0.7 mm along one or both edges. The (e.g. laser perforated) perforations (holes) are preferably spaced at 5 to 25 holes per cm (along the line of perforations), for example 10 to 25 holes per cm (along the line of perforations), for example 11 to 23 holes per cm (along the line of perforations). It will be appreciated that for a helical line of perforations the requirement for a clean break, rather than tearing, is less important and the holes may be spaced further apart. Preferably the perforations (holes) are of nominal dimensions 0.6 mm×0.3 mm, e.g. 0.4×0.2 mm. Preferably the holes (e.g. oval holes) are oriented with their longest axis (i.e. the hole length) perpendicular to the line of perforations.

The wrapper may be a paper (e.g. a plugwrap) or other sheet material. The paper is preferably a paper having basis weight of 15-50 gsm, more preferably 17-35 gsm. The paper may be air permeable, or impermeable (i.e. air impermeable except where the holes have been generated). The wrapper may be a cellulosic film or a cellulosic based film. The wrapper may be biodegradable. Preferably the wrapper has the ‘Ready Biodegradability’ level of biodegradability as measured according to OECD 301B ‘Ready Biodegradability’ method (modified Sturm test), which is well known in the art.

The individual (e.g. identical or substantially identical) filters or filter elements may include a substantially cylindrical core of tobacco smoke filtering material. The individual filter or filter element may further comprise a further wrapper. The further wrapper may be a paper (e.g. plugwrap).

The (individual) (e.g. identical or substantially identical) filters or filter elements may comprise a self-sustaining (longitudinally extending) cylindrical core. Herein, the term “self-sustaining” (as in “self-sustaining substantially cylindrical core”, “self-sustaining longitudinally extending substantially cylindrical core” etc.) means stable, rigid and self-supporting without requirement for a further wrapper (of e.g. plugwrap) to maintain its shape (e.g without requirement for a wrapper to hold the longitudinally extending continuous filaments in alignment to control the radius or circumference of the core).

The (individual) (e.g. identical or substantially identical) filters or filter elements may comprise a self-sustaining (longitudinally extending) cylindrical core comprising (e.g. formed from) a plurality of longitudinally extending substantially continuous filaments of tobacco smoke filtering material (e.g. cellulose acetate tow) which are bonded at their points of contact. In another example, the filters or filter elements may comprise a self-sustaining (longitudinally extending) cylindrical core comprising (e.g. formed from) a plurality of randomly oriented (e.g. individual or staple) fibres of tobacco smoke filtering material (e.g. cellulose acetate) which are bonded at their points of contact.

Preferably the continuous filaments of tobacco smoke filtering material (or randomly oriented fibres of tobacco smoke filtering material) are continuous filaments (or randomly oriented fibres) of cellulose acetate tow. Preferably the tobacco smoke filtering material (e.g. cellulose acetate, cellulose acetate fibres or filaments) is crimped. Preferably the filaments (or fibres) are bonded at their points of contact with a bonding constituent, e.g. a plasticiser (e.g. a plasticiser which has been activated or cured to bond the filaments at their points of contact). The self-sustaining longitudinally extending cylindrical core may be, for example, a cylindrical rod of circular cross section. The self-sustaining longitudinally extending cylindrical core may be of other shape, for example the self-sustaining longitudinally extending cylindrical core may be of annular cross section such that the self-sustaining longitudinally extending cylindrical core is a longitudinally extending hollow tube comprising (e.g. formed from) fibres or filaments of tobacco smoke filtering material bonded at their points of contact.

The individual (e.g. identical or substantially identical) filters and/or filter elements may further comprise one or more continuous components extending substantially longitudinally (e.g. longitudinally) of the cylindrical core. The (or a, or each) continuous component may be a thread or yarn or tape or continuous extruded element, for example a cotton thread, a cellulose acetate yarn, or a continuous extruded element of e.g. cellulose acetate such as that disclosed in WO2011/058319. Cigarette filters which include a thread or tape element, typically longitudinally aligned therein, are well known in the prior art. They are often referred to as “Thread Filters”. Thread Filters were originally proposed in U.S. Pat. No. 4,281,671, in which a cotton sewing thread was the preferred element. U.S. Pat. No. 4,281,671 also disclosed how the thread could be coloured, e.g. with different colours denoting different flavours. U.S. Pat. No. 4,281,671 discloses Thread Filters which require a wrapper around the tobacco smoke filtering material (and thread); it does not disclose filters or filter elements which include a thread but which are self sustaining (i.e. stable, rigid and self-supporting without requirement for a further wrapper).

The (or a, or each) continuous component extending longitudinally of the cylindrical core may be coloured or tinted, e.g. using appropriate dyes or pigments, preferably those with regulatory approval for use in food contact applications. The (or a, or each) continuous component may be of a contrasting colour to the tobacco smoke filtering material. In an example, the (or a, or each) continuous component further comprises a dye or pigment (e.g a dye or pigment which has regulatory approval for use in food contact applications). The dye or pigment may preferably be any colour which contrasts with the (e.g. white) tobacco smoke filtering material, for example green, blue, red, orange etc. If two or more continuous components extending substantially longitudinally (e.g. longitudinally) of the cylindrical core are present, the first continuous component may be of the same colour, or a different colour, to the second continuous component. The use of coloured component(s) (e.g. coloured cotton thread or threads) provides a product filter, element or rod with a distinctive end appearance that is useful for anti-counterfeit purposes.

The continuous component may bear a smoke modifying agent such as a flavouring agent. The flavouring agent may be any flavouring agent known for use in tobacco smoke filters or filter elements. For example, the flavouring agent may be menthol, spearmint, peppermint, nutmeg, cinnamon, clove, lemon, chocolate, peach, strawberry, vanilla etc. The agent may contain nicotine or a salt or derivative thereof. Preferably the flavouring agent is menthol.

The individual (e.g. identical or substantially identical) filters or filter elements may include an additive (e.g. an adsorbent). The additive may be a particulate additive. The particulate additive may any particulate additive suitable for use in a tobacco smoke filter—e.g. activated carbon, zeolite, ion exchange resin (e.g. a weakly basic anion exchange resin), sepiolite, silica gel, alumina, molecular sieves, carbonaceous polymer resins and diatomaceous earths. The particulate additive may be a mixture of two, or more, materials. The additive may include a flavourant—e.g. menthol—e.g. the additive may be sepiolite granules to which menthol has been applied. The individual (e.g. identical or substantially identical) filters or filters element may comprise a longitudinally extending core of tobacco smoke filtering material and an additive (e.g. carbon) with at least one end free of additive (to present a clean end to the smoker). The individual filters or filters element may be ‘monocarbon’ filters or filter elements—i.e. a filters/elements including a single longitudinally extending core of filtering material and additive (e.g. carbon) that has at least one end free of additive and e.g. which can be manufactured in a one-pass process (e.g. the ‘Active Patch’ filter, as disclosed in, for example, GB 2261152, and the ‘Smooth Core’ filter, as disclosed in, for example, WO 2006/059134).

The individual (e.g. identical or substantially identical) filters may comprise: a downstream (e.g. longitudinally extending, e.g. substantially cylindrical) core of tobacco smoke filtering material; an upstream (e.g. longitudinally extending, e.g. substantially cylindrical) core of tobacco smoke filtering material spaced longitudinally (upstream) of the downstream core; a wrapper (e.g. an outer wrapper) engaged around and joining the spaced upstream and downstream cores to define a cavity between the spaced upstream and downstream cores. The filter may include an additive in the cavity such that the individual filters are triple granular filters. The tobacco smoke filter or filter element may be of circumference 14 to 28 mm, for example 16 to 26 mm, for example 16 to 19 mm (e.g. 17.5 mm) or 24 to 25 mm. A tobacco smoke filter of the invention may be of length 10 to 40 mm, e.g. 11 to 25 mm, e.g. 12 to 16 mm, e.g. 14 mm. A tobacco smoke filter element of the invention may be of length 5 to 30 mm, e.g. 6 to 20 mm, e.g. 8 to 15 mm, e.g. 10 to 12 mm.

Filters and filter elements from product rods according to all aspects of the invention may be used generally as (or in) a filter tip for use with a individually rolled cigarette (e.g. a hand rolled cigarette) or a Roll Your Own or Make-Your-Own product.

According to the present invention in a further aspect there is provided a method of producing a product rod comprising a plurality (e.g 2 or more, e.g. 4 to 6) of individual (e.g. identical or substantially identical) tobacco smoke filters or filter elements abutted end to end, and a wrapper engaged around the plurality of filters or filter elements, wherein the wrapper includes perforations; the method comprising:

applying a wrapper to a longitudinally advancing flow comprising pluralities (groups) of individual (e.g. identical or substantially identical) filters or filter elements arranged between (e.g. pre-formed) dual filter rods, each dual filter rod comprising two (e.g. identical or substantially identical) filters/elements joined end to end, wherein the filters/filter elements and filter rods are abutted end to end [to thereby form a continuous wrapped rod comprising pluralities (groups) of abutted filters or filter elements arranged between (and abutted to) dual filter rods];

cutting the continuous wrapped rod in register with the dual filter rods such that the dual filter rod is cut into two individual filters/filter elements, to thereby provide a plurality of product rods each comprising (e.g. identical or substantially identical) filters or filter elements; perforating the wrapper (e.g with a laser).

The wrapper may be perforated such that it has a line of perforations in register with the or each junction between abutted filters/filter elements/dual filter rods. The wrapper may be perforated such that it has a line of perforations extending from one end of the product rod to the other end and defining a helix about the periphery (outer surface) of the product rod. The perforations (holes) may be any shape, e.g. oval or rectangular. Preferably the perforations (holes) are symmetrical. The perforations (holes) may be made by any means known in the art, e.g. laser, mechanical means or electrostatic means. The (e.g. laser perforated) perforations (hole) dimensions may be 0.1 mm to 0.7 mm along one or both edges. The wrapper may be perforated with (e.g. laser perforated) perforations (holes) which are preferably spaced at 5 to 25 holes per cm (along the line of perforations), for example 10 to 25 holes per cm (along the line of perforations), for example 11 to 23 holes per cm (along the line of perforations).

Preferably the wrapper is perforated with perforations (holes) of nominal dimensions 0.6 mm×0.3 mm, e.g. 0.4×0.2 mm. Preferably the wrapper is perforated with the perforations (e.g. oval holes) oriented with their longest axis (i.e. the hole length) perpendicular to the line of perforations.

According to the present invention in a still further aspect there is provided a method of producing a product rod comprising a plurality (e.g 2 or more, e.g. 4 to 6) of individual (e.g. identical or substantially identical) tobacco smoke filters or filter elements abutted end to end, and a wrapper engaged around the plurality of filters or filter elements, wherein the wrapper includes perforations; the method comprising:

applying a perforated wrapper to a longitudinally advancing flow comprising pluralities (groups) of individual (e.g. identical or substantially identical) filters or filter elements arranged between (e.g. pre-formed) dual filter rods, each dual filter rod comprising two (e.g. identical or substantially identical) filters/elements joined end to end, wherein the filters/filter elements and filter rods are abutted end to end [to thereby form a continuous wrapped rod comprising pluralities (groups) of abutted filters or filter elements arranged between (and abutted to) dual filter rods];

cutting the continuous wrapped rod in register with the dual filter rods such that the dual filter rod is cut into individual (e.g. identical or substantially identical) filters/filter elements, to thereby provide a plurality of product rods each comprising filters or filter elements.

The wrapper may be perforated such that it has a line of perforations in register with the or each junction between abutted filters/filter elements/dual filter rods. The wrapper may be pre-perforated with (lateral) lines of perforations aligned across the width of the wrapper, each row being separated from the adjacent row by a distance corresponding to the length of a single filter/filter element. In the case, the method may include a step of aligning/registering the lateral lines of perforations with the junctions between abutted filters/filter elements (e.g. prior to or during wrapping). In another example the method includes a step of generating—e.g. with a laser—(lateral) lines of perforations across the width of the (non-perforated) wrapper prior to, preferably immediately prior to, application of the wrapper.

The perforations (holes) may be any shape, e.g. oval or rectangular. Preferably the perforations (holes) are symmetrical. The perforations (holes) may be made by any means known in the art, e.g. laser, mechanical means or electrostatic means. The (e.g. laser perforated) perforations (hole) dimensions may be 0.1 mm to 0.7 mm along one or both edges. The (e.g. laser perforated) perforations (holes) are preferably spaced at 5 to 25 holes per cm (along the line of perforations), for example 10 to 25 holes per cm (along the line of perforations), for example 11 to 23 holes per cm (along the line of perforations). Preferably the perforations (holes) are of nominal dimensions 0.6 mm×0.3 mm, e.g. 0.4×0.2 mm. Preferably perforations (e.g. oval holes) are oriented with their longest axis (i.e. the hole length) perpendicular to the line of perforations.

The wrapper may be pre-perforated such that it has a line of perforations extending from one end of the product rod to the other end and defining a helix about the periphery of the product rod. The wrapper may be a cellulosic film or a cellulosic based film. The wrapper may be biodegradable. Preferably the wrapper has the ‘Ready Biodegradability’ level of biodegradability as measured according to OECD 301B ‘Ready Biodegradability’ method (modified Sturm test), which is well known in the art.

Preferably the wrapper is a paper (e.g. plugwrap). The (e.g. individual e.g. pre-formed) filters and/or (e.g. individual e.g. pre-formed) filter elements in the flow (of filters or filter elements) are preferably aligned such that the longitudinally axes of their cylindrical cores are oriented along the longitudinal direction of the flow.

The invention includes any filter cigarette made using a filter according to the invention.

The present invention will now be illustrated with reference to the following Examples and the attached drawings in which

FIG. 1 schematically illustrates a product rod of filters according to an embodiment of the invention;

FIG. 2 is a different view of the product rod of filters of FIG. 1;

FIG. 3 schematically illustrates a method and apparatus which may be used to manufacture the product of e.g. FIGS. 1 and 2;

FIG. 4 illustrates a product rod of filters according to a further embodiment of the invention; and

FIG. 5 shows the results of testing products of the invention (Example 1).

FIGS. 1 and 2 show a NWA “Rip-a-Tip”™ product rod 1 according to one embodiment of the invention.

The product rod 1 comprises six individual tobacco smoke filters 3 each of around 17.5 mm circumference and length 14 mm abutted end to end. The individual tobacco smoke filters 3 are identical with each other. Each filter 3 includes a self-sustaining substantially cylindrical core formed from a plurality of longitudinally extending substantially continuous filaments of crimped cellulose acetate tow which are bonded at their points of contact (i.e. each filter 3 is a NWA filter). The product rod 1 also includes a wrapper 5 comprising paper of basis weight 25 gsm which is engaged around the filters 3 thereby forming a wrapped cylinder of six filter elements of length 84 mm. As is best seen in FIG. 2, the wrapper includes five lines of perforations 7, each line including thirty oval holes of hole size about 0.6×0.3 mm (aligned such that the length of each oval hole is aligned with the longitudinal axis of the product rod 1). Each line of perforations 7 is in register with a junction between two abutted filters 3 (in other words, in register with each region where adjacent filters or filter elements abut each other). The holes in the wrapper can be made by any means known in the art, e.g. laser, mechanical or electrostatic means; suitable methods are described below.

In use the smoker takes product rod 1 and pulls or bends the rod at the join closest to one end of the product rod (indicated by the line of perforations closest to the end) to snap off an individual filter; the filter is then used when rolling a RYO cigarette. The oval holes of hole size about 0.6×0.3 mm are sufficiently large that the consumer can see them on the outside of the finished rod 3, enabling him to clearly identify the point at which the rod should be snapped. The lines 7 of perforations (holes) enable a clean break between adjoining tips to be achieved—a jagged break would be unsightly and unacceptable to the consumer. The section of the outer wrapper 5 around the individual filter is retained and forms part of the filter to be used, rather than becoming redundant (and discarded) in the case of conventional Pop-a-Tips.

FIG. 3 shows a method and apparatus according to a further embodiment of the invention which may be used to manufacture the product of FIGS. 1 and 2.

As can be seen in FIG. 3 a flow of pre-formed filters 103 and pre-formed dual filter rods 103 a is longitudinally advanced in the direction of arrow 104 into a garniture unit 106.

The pre-formed (identical) filters 103 are each of around 17.5 mm circumference and length 14 mm. Each filter 103 includes a self-sustaining substantially cylindrical core formed from a plurality of longitudinally extending substantially continuous filaments of crimped cellulose acetate tow which are bonded at their points of contact. The pre-formed dual filter rods 103 a are each of around 17.5 mm circumference and length 28 mm. Each rod 103 a includes a self-sustaining substantially cylindrical core formed from a plurality of longitudinally extending substantially continuous filaments of crimped cellulose acetate tow which are bonded at their points of contact. The filters 103 are NWA filters and may, as well as dual rods 103 a, be manufactured by a process similar to that described in UK Patent No. 1169932 (U.S. Pat. No. 3,455,766), in which filaments of cellulose acetate tow to which a plasticiser has been applied are fed into a forming station where a belt is folded around the tow until the longitudinal edges of the belt are juxtaposed and the tow is confined within the belt; the tow is thus formed into a longitudinally extending cylinder by the belt. The belt is then moved to a heat treating station where a heating fluid (e.g. steam) is passed through the belt into contact with the tow to activate the plasticizer. The belt and tow therewithin are then moved through a cooling station where cool air or other fluid is passed through the belt into contact with the tow to deactivate the plasticizer, if necessary, and dry the tow by removal of condensed steam, whereby the tow is made rigid to form a continuous self sustaining and stable longitudinally extending rod. The continuous self sustaining and stable longitudinally extending rod is cut into base rods of filters for subsequent use also by methods well known in the art.

Conventional Pop-a-Tip manufacture takes place on a dual rod filter making machine. These machines are well known in the art and normally used for combining two different types of base rod, which are held in two different hoppers on the machine. For Pop-a-Tip manufacture the two hoppers are filled with the same base rod type and these base rods are cut down (to provide the required tip length), aligned in an end-to-end relationship, wrapped in transparent film and cut to the final required Pop-a-Tip length. In the process of making product rods according to the present invention the two hoppers of the dual rod filter making machine (not shown) are also filled with base rods of filters 103 manufactured as set out above. One hopper is used to cut down the base rods to individual filters 103 of the required tip length (14 mm) and the other hopper is used to cut down the base rods to dual filter rods 103 a of the required tip length (28 mm) and the dual rod machine is then set to arrange and align the filters 103 and dual filter rods 103 a in an end-to-end relationship such that each dual filter rod 103 is separated form the next rod 103 a by four individual filters 103 to provide the flow of pre-formed filters 103 and multiple (dual) filter rods 103 a. As can be seen in FIG. 3 the filters 103 are aligned and abutted end to end (i.e. there are no spaces between individual filters 103 or filters 103 and filter rods 103 a) prior to longitudinal advancement in the direction of arrow 104 into the garniture unit 106.

The garniture unit 106 includes a compression shoe 108 through which the aligned and abutted filters 103 and dual filter rods 103 a are passed prior to wrapping in the garniture. Compression shoes are known in the art for control of the final circumference of the finished rod.

A wrapper 105 of paper of basis weight 25 gsm is applied to the continuously advancing flow of filters or filter elements in the garniture 106 in the conventional manner, to thereby form a continuous wrapped rod 111 comprising groups of four individual filters 103 separated by dual filter rods 103 a. The continuous wrapped rod 111 is then cut in register with a position half way along each dual filter rod 103 a (see arrow 222) by methods known in the art to provide intermediate product rods of around 17.5 mm circumference and 84 mm length, each containing six individual, identical, 14 mm long filters 103 in a common paper wrapper.

It is essential that each line of perforation holes (in the above case these would be spaced 14 mm apart) are closely aligned with (in register with) the region where adjoining tips abut. This may be achieved by the use of an on-line laser perforation system (not shown) after each filter rod (e.g. of 84 mm length) has been assembled. Such a laser perforator generates holes around the periphery of the rod in defined locations in a manner that is well-known for the online perforation of filter ventilation holes during cigarette assembly. The laser perforator generates five lines of perforations around the periphery of the rod: each line includes thirty oval holes of hole size about 0.6×0.3 mm, e.g. 0.4×0.2 mm; and each line of perforations is in register with a junction between two abutted filters. The resulting perforated product rod is a product as shown in FIGS. 1 and 2.

It will be appreciated that there are other ways in which the perforations may be achieved, including: a) use of a pre-perforated wrapper in which the perforations are aligned in rows across the width of the wrapper, each row being separated from the adjacent row by a distance (e.g. 14 mm) corresponding to the length of the filter and then employing a suitable registration system to ensure that these rows are maintained in alignment with the flow of filter tips during filter rod assembly; and b) a system similar to (a) in which, rather than the wrapper being pre-perforated, a series of lateral perforation lines are generated in the (non-perforated) wrapper as part of the filter production process immediately prior to it being used to wrap the filter tips.

FIG. 4 shows a NWA “Rip-a-Tip”™ product rod 51 according to another embodiment of the invention.

The product rod 51 comprises six individual (identical) tobacco smoke filters 53 each of around 17.5 mm circumference and length 14 mm abutted end to end. Each filter 53 includes a self-sustaining substantially cylindrical core formed from a plurality of longitudinally extending substantially continuous filaments of crimped cellulose acetate tow which are bonded at their points of contact (i.e. each filter 53 is a NWA filter). The product 51 also includes a wrapper 55 comprising paper of basis weight 25 gsm which is engaged around the filters 53 thereby forming a wrapped cylinder of six filter elements of length 84 mm. The wrapper includes a lines of perforations 57 extending from one end of the product rod 51 to the other (end) and defining a helix (spiral) about the periphery of the product rod. The perforations are oval holes of hole size about 0.4×0.2 mm.

The holes in the wrapper can be made by any means known in the art, e.g. laser, mechanical or electrostatic means, e.g. by the methods described above. It will be appreciated that if the wrapper is pre-perforated (i.e. perforated before application to the filters/elements of the product rod), the perforations (holes) will have to be carefully located so they form a continuous helix after the wrapper is wrapped around the filters/elements.

In use of the embodiment of FIG. 4, the consumer peels back a strip of the wrapper along the helical line of perforations to allow individual filter tips to be sequentially released for use; the remaining portion of the wrapper holds the remaining filters in place. It will be appreciated that in this case the wrapper is discarded, rather than remaining part of the filter.

In another example (not shown) the pitch of the helix defined by the line of the perforations 57 (that is the distance along the helical axis and also along the product rod that results in one full turn of the helix) may be 14 mm, the length of a single individual filter or filter element. In this example, peeling back a single turn of the helix of the wrapper releases a single filter/filter element.

EXAMPLES Example 1

The applicants carried out trials to identify the most appropriate size and spacing of holes to enable (i) a clean break, or “snap” of the filter from the product rod and (ii) a suitable visual cue for the consumer.

The applicants made filter rods (of 17.9 mm circumference) similar to those shown in FIGS. 1 and 2, using NWA filters and a perforated plugwrap paper. The plugwrap paper was perforated with various numbers of either rectangular or oval holes of nominal dimensions 0.2×0.4 mm (with the length of hole orientated along the length of the paper/filter rods—in other words the holes are oriented with their longest axis (i.e. the hole length) perpendicular to the line of perforations). Measurements subsequently made using a microscope showed that the actual hole size was closer to 0.6×0.3 mm.

The manufactured rods were tested by “snapping” or pulling off one filter from the rest along the line of the perforations.

The following Table shows the results.

Number of holes Rectangular holes Oval holes 10 Uneven Uneven “snap”/tearing “snap”/tearing 15 Uneven Uneven “snap”/tearing “snap”/tearing 20 Uneven Fair ease of “snap”/tearing separation and quality of separation line 25 Fair ease of Good ease of separation and separation and quality of quality of separation line separation line 30 Good ease of Very good ease of separation and separation and quality of quality of separation line separation line (see FIG. 5) (see FIG. 5) 35 Very good ease of Excellent ease of separation and separation and quality of quality of separation line; separation line; rod unstable/weak rod unstable/weak

In all cases, the oval hole shape provides a smoother and more even separation line after ripping (“snapping”) an individual filter off the rod (FIG. 5).

The best results in terms of ease of separation and the quality of the separation line were obtained with 35 holes for rectangular hole shape; however, similar results were obtained with 30 holes for the oval hole shape (FIG. 5), and even better results in terms of ease of separation were obtained with 35 holes for oval hole shape. However, with 35 holes the rod became unstable and there is a risk of significant difficulty processing the plugwrap with this pattern in production and of the rod becoming unstable during packaging and transportation. Thus, the pattern with 30 oval shaped holes provides the best results in terms of ease of separation, rod stability and the quality of the separation line.

The example therefore shows that 30 to 35 rectangular or oval shaped holes of nominal dimensions 0.4×0.2 mm around the circumference of a 17.9 mm circumference Pop-a-Tip provide optimum ‘snap’ characteristics (see FIG. 5). Less than around 15 holes of such size give an uneven ‘snap’, whilst more than 35 or 40 holes can result in the paper being too weak to be processed on conventional filter making or packaging machinery.

Example 2

This Example measures the tensile strength of a plug wrap that has been perforated in accordance with aspects of the invention. The test is designed to assess the runnability of a pre-perforated paper on a filter making machine.

Strips of non-porous plug wrap paper of 27 gsm basis weight as supplied by Papierfabrik Wattens GmbH of Austria were perforated by laser providing an array of holes each nominally 0.4×0.2 mm. An array of holes were produced at 10, 20, 30, 40, 50 and 60 holes per 17.5 mm width and the tensile strength measured.

The results were as follows:

Number of Holes/17.5 mm Mean Tensile Strength (Kgf) 0 2.29 10 2.35 20 2.23 30 1.78 40 1.75 50 1.47 60 1.39

The test method involved cutting the plug into test pieces of 180 mm length×15 mm width, with each test strip having a single line of holes. Testing was carried out using a Lloyd L500 tensile tester, using a load range of 0-10.0 Kgf, extension range 0-1000 mm and crosshead speed set to ensure that the sample broke within 15 to 25 seconds.

A surprisingly high level of tensile strength was retained, even at the more extreme number of holes where the paper was visually almost completely cut through.

These data confirm the runnability of the plug wrap on filter making machines: even at the highest preferred level of 40 holes per 17.5 mm width, the loss of tensile strength was only around 25%. 

1. A product rod comprising a plurality of individual tobacco smoke filters or filter elements abutted end to end; and a wrapper engaged around the plurality of filters or filter elements, the wrapper including perforations.
 2. A product rod comprising a plurality of individual tobacco smoke filters or filter elements abutted end to end; and a wrapper engaged around the plurality of filters or filter elements, the wrapper including a line of perforations in register with the or each junction between abutted filters or filter elements.
 3. A product rod according to claim 1 wherein the individual tobacco smoke filters, or individual tobacco smoke filter elements, are identical or substantially identical.
 4. A product rod according to claim 1 wherein the wrapper is paper (e.g. a plugwrap) or other sheet material.
 5. A product rod according to claim 4 wherein the paper has basis weight of 15-50 gsm.
 6. A product rod according to claim 1 which includes a line of 16 to 39 perforations in register with the or each junction between abutted filters or filter elements.
 7. A product rod according to claim 1 wherein the perforations are symmetrical.
 8. A product rod according to claim 1 wherein the perforations are oval or rectangular.
 9. A product rod according to claim 1 wherein the perforations are of approximate dimensions 0.1 mm to 0.7 mm.
 10. A product rod according to claim 1 wherein the perforations are spaced at 10 to 25 holes per cm.
 11. A product rod comprising a plurality of individual tobacco smoke filters or filter elements abutted end to end; and a wrapper engaged around the plurality of filters or filter elements, the wrapper including a line of perforations extending from one end of the product rod to the other end and defining a helix about the periphery of the product rod.
 12. A product rod according to claim 11 wherein the pitch of the helix defined by the line of the perforations is the length of a single individual filter or filter element.
 13. A product rod according to claim 11 wherein the perforations are symmetrical.
 14. A product rod according to claim 11 wherein the perforations are oval or rectangular.
 15. A product rod according to claim 11 wherein the perforations are of approximate dimensions 0.1 mm to 0.7 mm.
 16. A product rod according to claim 11 wherein the perforations are spaced at 5 to 25 holes per cm.
 17. A product rod according to claim 11 wherein the individual tobacco smoke filters, or individual tobacco smoke filter elements, are identical or substantially identical.
 18. A product rod according to claim 1 wherein the individual filters or filter elements include a substantially cylindrical core of tobacco smoke filtering material.
 19. A product rod according to claim 1 wherein the individual filters or filter elements include a self-sustaining (longitudinally extending) cylindrical core of tobacco smoke filtering material.
 20. A product rod according to claim 1 wherein the individual filters or filter elements include a self-sustaining (longitudinally extending) cylindrical core comprising (e.g. formed from) a plurality of longitudinally extending substantially continuous filaments of tobacco smoke filtering material (e.g. cellulose acetate tow) which are bonded at their points of contact.
 21. A product rod according to claim 1 wherein the individual filters or filter elements include a self-sustaining (longitudinally extending) cylindrical core comprising (e.g. formed from) a plurality of randomly oriented (e.g. individual or staple) fibres of tobacco smoke filtering material (e.g. cellulose acetate) which are bonded at their points of contact.
 22. A product rod according to claim 1 wherein the individual filters or filter elements include one or more continuous components extending substantially longitudinally (e.g. longitudinally) of the cylindrical core. 23-26. (canceled) 